When the doors of the TARDIS accidentally open in mid-flight, the Doctor,
Susan, Ian and Barbara emerge to find themselves reduced to just inches in
height. Barbara is poisoned by a new form of insecticide, while the others
try to stop the murderous plans of an unscrupulous businessman to market
the insecticide despite its devastating effects on the environment.

Production

The Doctor Who production team had always wanted a story in which
the main characters were shrunk to a fraction of their normal height. Such
a story had been proposed in the earliest format guide for the show,
completed by early May 1963. The format guide's author, CE Webber, then
developed the notion into a serial titled “The Giants“, which
was intended to be Doctor Who's premiere adventure. However, the
criticisms of Head of Drama (and Doctor Who creator) Sydney Newman
-- combined with the technical limitations of Doctor Who's original
studio, Lime Grove D -- ultimately put paid to “The Giants”.
It was rejected in mid-June, although elements from Webber's first episode
would be incorporated into the serial that took its place, 100,000 BC.

Subsequently, the idea of doing a “miniscules” story was
passed along to Robert Gould, and by mid-September, this was scheduled as
the fourth serial of the season. However, Gould's scripts hit problems,
and on February 4th, 1964, he and story editor David Whitaker agreed that
work on the adventure would cease. However, Whitaker had clearly not yet
given up on the idea: as of the end of February, a
“miniscules” tale was still planned as the penultimate story
of the production block, with Richard Martin intended to direct but no
writer yet lined up.

Louis Marks' scripts were the third attempt at a
“miniscules” story

Finally, in late March, Whitaker met with Louis Marks. Marks had written
for a variety of adventure and thriller series, including The
Adventures Of Robin Hood and Ghost Squad; he also held a Ph.D.
from Oxford. Marks agreed to make a third attempt at a
“miniscules” story, and was commissioned to write four
episodes on April 14th. The serial, originally called “The
Miniscules” and later Planet Of Giants, would be made as part
of Doctor Who's first recording block but held over for
transmission as part of Season Two. It was initially thought that
Planet Of Giants would be the second story of the new season.
However, when Chief of Programmes Donald Baverstock decided that
Doctor Who should run later into the summer before the break
between seasons, The Reign Of Terror was held
back to end the first batch of episodes, making Planet Of Giants
the second-season premiere.

Planet Of Giants was listed as Serial J, although the slot had
earlier being identified as Serial I. This would be the first of several
occasions when letters would be skipped to avoid confusion between
similar-looking characters (O and U would also, inconsistently, be avoided
over the years). Unlike Webber, whose storyline for “The
Giants” was largely action/adventure-oriented, Marks took the
opportunity to incorporate an environmental slant into Planet Of
Giants. He was heavily inspired in this regard by the 1962 Rachel
Carson text Silent Spring.

Despite earlier indications that Richard Martin would direct Planet Of
Giants, Martin was ultimately assigned to the subsequent serial,
The Dalek Invasion Of Earth. The man given the
director's chair for Serial J was Mervyn Pinfield, Doctor Who's
associate producer. Pinfield had previously handled the first four
episodes of The Sensorites. Work on Planet
Of Giants got under way with filming at the Ealing Television Film
Studios on July 30th. In cases in which the characters had to be seen
standing next to “giant” objects but for which it was
impossible or impractical to use oversized props -- such as Farrow's body
-- a film technique was used whereby the object was magnified by
projecting its image through a mirror onto black drapes. Unfortunately,
these shots did not turn out well and had to be remounted on August
13th.

Planet Of Giants was the final
Doctor Who story scheduled to be made at
Lime Grove Studio D

Planet Of Giants was the final Doctor Who serial scheduled
to be made in the programme's original studio home, Lime Grove D, before
Doctor Who shifted to the more spacious and modern confines of
Riverside 1. Part one was recorded on August 21st, with the other three
episodes to follow on subsequent Fridays. As recording began, producer
Verity Lambert had just secured confirmation of a second production block
for the series from Baverstock, after months of stalling. Baverstock
offered Lambert three more months of Doctor Who, with an option for
an additional three months.

However, when Lambert attempted to negotiate contract extensions with
William Hartnell, William Russell and Jacqueline Hill (having already
planned to write Carole Ann Ford out of the programme in The Dalek Invasion Of Earth), she encountered
resistance from all three actors. Hartnell, in particular, wanted
assurance that Doctor Who would continue for at least a full six
months, while each of them wanted more money than their producer was
offering. Lambert sought advice from both Baverstock and Head of Series
Elwyn Jones, who was standing in for the vacationing Newman.

Baverstock indicated that he might be willing to guarantee six months for
the new recording block. He also suggested that Doctor Who could be
rested for six weeks following The Dalek Invasion Of
Earth to give Lambert a chance to find new actors (possibly even
overhauling the entire cast). Jones, however, was not happy with the
latter possibility, and instead suggested that Hartnell might be able to
carry the series by himself for a few episodes if necessary. Ultimately,
however, the six-month assurance and compromise pay raises enabled Lambert
to sign all three performers.

Production on Planet Of Giants wound up with the recording of part
four, The Urge To Live, on September 11th. Pinfield was otherwise
engaged on this date so the episode was directed instead by Douglas
Camfield. Camfield had worked at the BBC since 1955 in several different
capacities, including scriptwriter, assistant film editor and production
assistant. It was in this latter role that Camfield had worked with Waris
Hussein on both 100,000 BC and Marco Polo, and Hussein had allowed Camfield to
direct some of the filmed sequences. This led to his being hired for
The Urge To Live, and Lambert was extremely pleased with his work
on the installment.

Donald Wilson felt that Planet Of
Giants would be made more exciting by trimming it to three
parts

In viewing the finished Planet Of Giants, however, Head of Serials
Donald Wilson decided that the story, burdened by a lack of resources,
would make for an underwhelming start to the new season. Wilson's
preference was to delay it until after The Dalek
Invasion Of Earth, but Susan's departure in that adventure made
this impossible. Instead, on October 19th he asked that Planet Of
Giants be trimmed down to just three parts, in the hope that this
would make it as exciting as possible.

To accomplish this, it was decided that the final two installments --
Crisis and The Urge To Live -- would be edited together,
with both episodes losing roughly half of its content. Amongst the more
significant cuts were Barbara and Ian watching as the cat dies of DN6
poisoning; the Doctor deducing why Farrow was killed and declaring that he
must stop Forester; additional phone conversations between Forester and
Hilda; Ian and Barbara being consumed by Smithers' cigarette smoke; the
TARDIS crew being startled by a tone sent down the phone line by Hilda
because Smithers' phone is off the hook; and Smithers beginning to realise
Forester has been lying to him about Farrow's death and DN6. The
resulting hybrid episode was entitled Crisis, and only Camfield
was credited as director.